Oscar is the magician’s hand, charged with collecting plants to concoct spells, and lives happily hidden away, with his cats, in the cellar of Master Caleb’s shop in the Barrow, outside the walled city of Asteri. (Ursu subtly delineates tics that suggest 11-year-old Oscar may be autistic.) Then Master Caleb disappears for mysterious obligations on the continent, and the bane of Oscar’s existence, the magician’s apprentice, is killed. Oscar’s world crumbles. Unprepared to deal with customers, he receives help from the Healer’s apprentice, Callie, but Oscar realizes his inability to make small talk is more than shyness: there is something off about him. It gets worse: his garden is ravaged, the city’s children fall ill, and a monster stalks the countryside. It’s left to Oscar and Callie to save Asteri. Adult readers will savor Ursu’s allusions to well-known fairy tales—most significantly, Pinocchio—and appreciate the many well-turned phrases. But the story has some gaps, and a message about the failings of magic may disappoint younger fantasy fans. Final art not seen by PW. Ages 8–12. Author’s agent: Tina Wexler, ICM. Illustrator’s agent: Susan Cohen, Writers House. (Oct.)